Hi,
As the others have nicely pointed out, the formula 1/sqrt(LC) does not give you what we usually call the frequency F until after you also divide by 2*pi. What it does give you is a frequency, but we usually call that frequency the "angular frequency" and use the lower case greek letter which looks almost like a lower case English "w" and using the symbol editor it is printed as: "ω".
So we have:
w=1/sqrt(LC)
and
f=w/(2*pi)
Most electrical simulators plot the frequency "f" in Hertz, and that is what yours plotted too.